The invention relates generally to conductors for interconnecting components. It relates specifically to a flexible circuit conductor run.
It has been known to use a flexible circuit conductor run for connecting circuit elements, so as to transfer signals therethrough, in devices such as communications devices, computers, or the like. The conductors in such conductor runs consist of a plurality of pairs of generally parallel spaced-apart thin conductors, as in Baldyga U.S. Pat. No. 4,129,939, Walton U.S. Pat. No. 4,092,057, Luetzow U.S. Pat. No. 3,818,122, and Reyner II et al U.S. Pat. No. 3,818,117.
Impedance is the square root of the ratio of inductance to capacitance. Every conductor has impedance resulting from magnetic fields generated by current flow therethrough.
Impedance matching is particularly important for conductors at higher power and frequencies, used presently for faster operation, greater signal resolution, and improved precision in components.
However, as signal power and frequencies increase, impedance mismatch becomes a greater problem, because energy is absorbed in creating and releasing radiating magnetic fields, conductor runs assume dynamic properties and interact with systems producing unwanted effects, and fields from adjacent conductors interact to transfer signals from one to the other producing undesirable crosstalk effects.
Further, as component sizes decrease to provide greater functionality in each component, each increase in functional density results in a corresponding reduction in power consumption and power delivery, which in turn necessitates higher quality circuit interconnections.
In order to transfer signals effectively between circuit elements through a flexible circuit conductor run, the characteristic impedance of the circuit elements and the conductor run, at high operating power and frequencies, should be substantially matched, i.e. they should be substantially within operating tolerances. Impedance mismatch results in reduced energy transfer and increased signal distortion.
It has been further known to provide electrically conductive flat cable strips with the paths of each pair of conductors crossing one another at periodic strip locations, to significantly reduce crosstalk between wires in the cable, as in Balde U.S. Pat. No. 3,764,727. It has been still further known to provide twisted pairs of flat conductor cable with different pseudo-twisted pairs of conductors, adapted to control capacitance by decreasing the area of crossover region, as in Ganrud U.S. Pat. No. 3,761,842. However, the problems regarding matching characteristic impedances of the circuit elements and flexible circuit conductor run at high operating power and frequencies are not addressed in such devices.